package demo1;
import java.util.Stack;
import java.util.*;
/**
 * @Author liangzai
 * @Description:
 */
public class MyStackUsQueue {
    public Queue<Integer> queue1;
    public Queue<Integer> queue2;

    public MyStackUsQueue() {
        queue1 = new LinkedList<>();
        queue2 = new LinkedList<>();
    }
    /**
     * 入栈
     * @param x
     */
    public void push(int x) {
        if(empty()) {
            queue1.offer(x);
            return;
        }
        if(!queue1.isEmpty()) {
            queue1.offer(x);
        }else {
            queue2.offer(x);
        }
    }
    /**
     * 出栈
     * @return
     */
    public int pop() {
        if(empty()) {
            return -1;
        }
        if(!queue1.isEmpty()) {
            int size = queue1.size();
            for (int i = 0; i < size-1; i++) {
                queue2.offer(queue1.poll());
            }
            return queue1.poll();
        }else {
            int size = queue2.size();
            for (int i = 0; i < size-1; i++) {
                queue1.offer(queue2.poll());
            }
            return queue2.poll();
        }
    }
    /*
    获取栈顶元素
     */
    public int top() {
        if(empty()) {
            return -1;
        }
        if(!queue1.isEmpty()) {
            int size = queue1.size();
            int ret = -1;
            for (int i = 0; i < size; i++) {
                ret = queue1.poll();
                queue2.offer(ret);
            }
            return ret;
        }else {
            int size = queue2.size();
            int ret = -1;
            for (int i = 0; i < size; i++) {
                ret = queue2.poll();
                queue1.offer(ret);
            }
            return ret;
        }
    }
    /*
    栈是否为空
     */
    public boolean empty() {
        return queue1.isEmpty() && queue2.isEmpty();
    }
}
